Without knowing their names a man and woman have sex. Afterwards they introduce themselves and begin an affair. The woman feels empty without a man. The man is married with a child but he needs more than what his wife can provide.
On a crowded train, an office lady, Rika, is attacked. When Rika turns around, she lets out a cry of shock. The man is Tatsuo, who is married to Rika's co-worker, Miho. Later, Rika visits Miho's house and confesses what Tatsuo did to her, but...
